Bis-isoxazole tetranitrate (BITN): a high-energy propellant plasticizer and melt-castable eutectic explosive ingredient
Inventors
Sabatini, Jesse J. • Drake, Gregory W • Wingard, Leah A.
Assignees
United States Department of the Army
Publication Number
US-9994532-B1
Publication Date
2018-06-12
Expiration Date
2037-08-25
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Abstract
A method and compound includes mixing a salt compound to 2-butyne-1,4-diol in an alcohol to create a mixture; adding a solution of dichloroglyoxime in an alcohol to the mixture to create 3,3′-bis-isoxazole-4,4′,5,5′-tetryltetramethanol; and nitrating the 3,3′-bis-isoxazole-4,4′,5,5′-tetryltetramethanol to create 3,3′-bis-isoxazole-4,4′,5,5′-tetrylbis(methylene) tetranitrate, which has the structural formula: The alcohol may include ethanol, wherein the adding may occur at 60° C., or alternatively the adding may occur at 80° C. The alcohol may include n-butanol, wherein the adding may occur at 100° C., or alternatively the adding may occur at 120° C. The mixing may occur at 120° C. The method may further include cooling the nitrated 3,3′-bis-isoxazole-4,4′,5,5′-tetryltetramethanol to 0° C.; stirring the cooled nitrated 3,3′-bis-isoxazole-4,4′,5,5′-tetryltetramethanol for at least four hours creating a precipitate; warming the precipitate; pouring the precipitate onto ice while stirring creating a solid material; collecting the solid material; and drying the solid material to yield the 3,3′-bis-isoxazole-4,4′,5,5′-tetrylbis(methylene) tetranitrate.
Core Innovation
The invention provides a new energetic molecule, 3,3′-bis-isoxazole-4,4′,5,5′-tetrylbis(methylene) tetranitrate (BITN), and a method for its synthesis. The synthesis involves mixing a salt compound with 2-butyne-1,4-diol in an alcohol, adding a solution of dichloroglyoxime to form 3,3′-bis-isoxazole-4,4′,5,5′-tetryltetramethanol, and subsequently nitrating this compound to yield BITN.
The BITN molecule serves dual functions as both an energetic plasticizer in rocket and gun propellant formulations and as a melt-castable eutectic explosive ingredient. BITN possesses weak Lewis basic functionality, which allows favorable interaction with nitrocellulose (NC), improving wetting and surfactant properties in double-base formulations. Unlike traditional nitrate ester plasticizers such as nitroglycerin (NG), BITN contains primary nitrate functionalities, which enhance thermal stability and reduce volatility.
The background section identifies the problem of developing high-energy density materials (HEDMs) that combine good performance with low sensitivity and environmental safety. Traditional melt-cast materials like TNT have environmental issues, while alternatives such as DNAN provide lower explosive power. Existing nitrate-based plasticizers like NG suffer from high thermal instability, volatility, and sensitivity issues, leading to safety concerns during processing and use. Hence, there is a need for new high-energy plasticizers and melt-castable materials that provide improved power, thermal stability, reduced sensitivity, and safer synthesis pathways.
Claims Coverage
The patent includes two independent claims covering a method of synthesizing BITN and the BITN compound itself, encompassing the key inventive features of the synthesis process and molecular structure.
Method for synthesizing BITN
A method comprising mixing a salt compound with 2-butyne-1,4-diol in an alcohol to form a mixture, adding a solution of dichloroglyoxime in an alcohol to produce 3,3′-bis-isoxazole-4,4′,5,5′-tetryltetramethanol, and nitrating this tetramethanol to produce 3,3′-bis-isoxazole-4,4′,5,5′-tetrylbis(methylene) tetranitrate.
Compound structure of BITN
The compound characterized by the specific structural formula of 3,3′-bis-isoxazole-4,4′,5,5′-tetrylbis(methylene) tetranitrate as defined and produced by the described synthesis method.
The claims collectively cover the innovative synthesis method for producing BITN and the novel BITN compound itself, emphasizing the specific chemical processes and resulting molecular architecture.
Stated Advantages
BITN has high thermal stability with a decomposition onset at 193.7°C, higher than most nitrates.
BITN exhibits impact, friction, and electrostatic discharge sensitivities comparable to PETN, making it suitable for pyrotechnic primer formulations.
The molecule has a melting point ideal for melt-castable eutectic explosive formulations and can serve as a high-energy plasticizer with improved performance over existing plasticizers like nitroglycerin.
BITN interacts favorably with nitrocellulose, providing improved wetting and plasticization enhancing propellant mechanical properties and reducing sensitivity issues.
The synthesis method offers a cost-effective alternative by enabling the reaction of internal alkynes with hydroximoyl chlorides without the need for expensive catalysts and absence of chromatography purification.
Documented Applications
Ingredient in melt-castable eutectic explosive formulations, replacing TNT, RDX, and DNAN-based materials.
Energetic plasticizer replacement for diethylene glycol dinitrate (DEGDN), triethylene glycol dinitrate (TEGDN), and non-energetic plasticizers like phthalates and triacetin in rocket and gun propellant applications.
Plasticizing ingredient in double-base propellant formulations to improve wetting and plasticization of nitrocellulose.
Pyrotechnic ingredient in primer formulations, including manufacturing civilian firearm primers.
Ingredient in pressed and/or extruded dynamite formulations offering enhanced thermal stability and reduced volatility.
General use as high-energy fuel in applications requiring nitroglycerin-like power, including enhanced handling and processing safety in castable minimum signature rocket propellants.
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